BOSTON — The so-called bid book that Boston business leaders presented last year to the United States Olympic Committee helped the city win the competition over Los Angeles, San Francisco and Washington as America’s candidate to host the 2024 Summer Games.

But now, that document may end up being the city’s undoing.

Boston 2024, the group of private business leaders who crafted the bid last year out of public view, has maintained that the Games would be paid for with private money.

But the bid book, which was obtained this week by local news organizations, said the opposite — that the Games would also need public money.

Boston 2024 said that the bid book was in the “proof of concept” stage and that the group was preparing a new plan, with new financial figures and new venues, to release in late June. “We stand by our commitment that the operations of the Games and the building of venues will be privately funded,” Boston 2024 said in a statement.

But the discrepancy over funding added fuel to the fire for the many vociferous critics in Boston, where public support for hosting the Games had already sagged below the halfway mark and where earlier stumbles had prompted at least one Olympics official to put the city on notice.

“Right now the U.S.O.C. is going through a similar vetting process to make sure Boston is the right city,” Angela Ruggiero, an American women’s hockey team gold medalist and a member of the United States Olympic Committee and the International Olympic Committee, told the Boston City Council this month. “So there’s no guarantee Boston will be the city in September.”

That is when the U.S.O.C. must formally submit an American city to the I.O.C., which also will most likely be considering bids from Paris; Rome; and Hamburg, Germany. The I.O.C. will choose the winner in 2017.

The discrepancy between the bid book and what Boston 2024 told the public was only the most damning piece of news to emerge in a week of bad news for Olympic boosters. On Thursday night, the adjacent town of Brookline voted overwhelmingly to oppose the bid, saying Boston 2024 had never informed the town that it wanted to use the Country Club, which is in the town and is the oldest club of its kind in the United States, as a venue for golf.

And Gov. Charlie Baker, a Republican, indicated that he was blindsided by Boston 2024’s plans to rely on a $1 billion expansion of the city’s convention center for several Olympic events — expansion plans that he had frozen this year in response to the state’s fiscal woes.

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A public forum was held in February in Boston. The details of the bid, which were obtained this week by local news organizations, showed the proposal for the Games included the use of public money.CreditCharles Krupa/Associated Press

“No one ever brought it to my attention,” Mr. Baker told reporters. “It was never a part of the conversation. Ever. Not once, O.K.? Never.”

Taken together, these latest developments are leading some observers to conclude that it is only a matter of time before the U.S.O.C. pulls the plug on Boston. The U.S.O.C. in March strongly denied a report in The Wall Street Journal that it had spoken with Los Angeles and San Francisco about reviving their bids if public support in Boston did not improve.

“I think we’ve seen the beginning of the end,” said Dan Payne, a Democratic political analyst here. “It’s like a soap opera.”

Joseph Giglio, who teaches corporate strategy at Northeastern University, said, “What’s transpired this week is just validating the public’s suspicions about the motivations and competency of Boston 2024.”

Boston 2024 has been reeling for some time. The committee had stumbled so often — it pledged, for example, to pay former Gov. Deval Patrick $7,500 a day to be a “global ambassador” for the Games — that just eight days ago, it underwent a leadership shake-up. The group removed its chairman, John Fish, this region’s biggest construction magnate, and replaced him with Steve Pagliuca, an executive at Bain Capital and co-owner of the Boston Celtics.

But while Mr. Pagliuca and other Boston 2024 officials were in Switzerland this week becoming acquainted with the I.O.C., things at home were unraveling.

One of residents’ biggest concerns about hosting the Olympics has always been a fear of being stuck with the tab for the inevitable cost overruns. So Boston 2024 has publicly insisted all along that it would pay for the Games with private money — through broadcast revenue, corporate sponsorships and ticket sales — except for security, which the federal government would underwrite.

But this week, Boston Business Journal and Boston Magazine obtained the complete bid book through the Freedom of Information Act. In parts that had been redacted for the public, the book showed that the committee would depend on public money in the form of city- or state-issued tax increment financing bonds to pay for land acquisition and infrastructure costs at the site of a proposed Olympic stadium.

“New disclosures indicate Boston 2024 used rosy assumptions and the promise of public funding to win the U.S. Olympic Committee’s backing to potentially host the 2024 Summer Games,” Boston Business Journal wrote.

Critics seized on the reports as evidence that Boston 2024 had been deceptive and that taxpayers would indeed be on the hook. Chris Dempsey, a chairman of No Boston Olympics, the main opposition group, called the disclosure a “smoking gun.”

Senator Elizabeth Warren of Massachusetts, who has been skeptical but largely noncommittal on whether Boston should host the Olympics, was among those who seemed annoyed. She said this week that when she had met earlier with the committee, “they did not disclose” the funding mechanism. “I’ve said all along, I want to know where the money’s coming from and where the money’s going to be spent,” she said.

A version of this article appears in print on , on Page D1 of the New York edition with the headline: Details of Boston’s ’24 Bid May Jeopardize Its Future . Order Reprints | Today’s Paper | Subscribe